Heart Murmur In Babies: Causes, Symptoms And Treatment

Written by Rohit Garoo Experience: 9 years
Last Updated on

The heart beats rhythmically, which gives it the characteristic lub-dub sound. Usually, you will not hear anything between the beats. But sometimes, there is an extra noise, referred to as a heart murmur.

What is the source of these murmurs? Do they indicate a problem? Continue reading this MomJunction post to understand heart murmur in babies, its causes, and when you should worry about it..

What Is A Heart Murmur In Babies?

Heart murmurs are the abnormal heart noises that occur between the ‘lub’ and ‘dub’ sounds.

The heart has two sections: the top atria (singular: atrium) and the bottom ventricles. Each section is split into two chambers called the left chamber and right chamber. The blood enters the heart via the atria and is pumped out of the heart via the ventricles.

When the atria pump the blood through the valves to the ventricles, the “lub” sound, also referred to as S1, is made. When the heart pumps the blood out of the ventricles (and eventually out of the heart itself), the “dub” sound, or S2, is created. The pause between S1 and S2 (lub and dub) is called systole, and the pause between S2 and S1 (dub and lub) is called diastole. Usually, these pauses are silent. But at times you hear a noise or a ‘murmur’ instead.

The heart murmur can be a systolic heart murmur or diastolic heart murmur.

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How Do Heart Murmurs Sound?

A heart murmur sounds like a whooshing, blowing or rasping sound between the beats (1). Unlike the thumping ‘lub-dub’ sound, a heart murmur is significantly different with a higher or lower frequency. Heart murmurs can also be prominent enough to make the lub-dub unidentifiable, making it hard to determine when lub ended, when dub started, and vice-versa.

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[ Read: Baby Congenital Heart Disease Symptoms ]

Are Heart Murmurs In Babies Unusual?

According to the American Academy of Pediatrics, heart murmurs are quite common and mostly normal, which means that they do not necessarily indicate a problem (2).

Infants and toddlers mostly have “innocent” or functional heart murmurs, which are a regular occurrence throughout childhood (3). These heart murmurs do not pose a threat since they originate from the regular contraction of the heart muscles, valves, and the flow of blood within the heart. Babies or toddlers with innocent heart murmurs are healthy and need no medical attention. About 85% of babies have innocent heart murmurs that go away as they grow.

But sometimes heart murmurs are not exactly innocent and could indicate an anomaly.

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What Are The Causes Of A Heart Murmur?

The following are the most common causes of heart murmurs in babies and toddlers (4):

  • Stenosis: Stenosis is the narrowing down of a blood vessel, tube or duct in the heart (5). The type and name of the stenosis affecting the child depends on the site of occurrence. For instance, pulmonary stenosis happens when the pulmonary artery narrows down (6). Other types of stenosis are aortic stenosis and subaortic stenosis.
  • Congenital heart defects: Pediatric experts state that about one in 100 infants is born with a structural defect in the heart (7). A common heart defect in children is the ventricular septal defect, or a hole in the ventricular septum, which is a layer of tissue separating the right ventricle from the left one (8). Another septal defect is the atrial septal defect.
  • Valve regurgitation: In this condition, the valves of the heart do not close completely. It causes a small amount of blood to trickle backwards, which can cause complications including heart murmur. Examples of valve regurgitation issues are tricuspid valve regurgitation and mitral valve regurgitation.

The heart is a complex organ, and several issues can lead to a heart murmur. Eventually, the type of heart murmur will help determine the underlying problem. While you may not be able to diagnose the murmurs as a doctor would do, you can watch out for the signs and symptoms of a heart murmur in the baby.

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[ Read: Baby Down Syndrome Signs ]

What Are The Symptoms Of Problematic Heart Murmurs In Babies?

The following symptoms could indicate problems in the heart that cause heart murmurs in the baby (9):

  • Rapid and labored breathing.
  • An inexplicable and recurrent cough without cold and flu.
  • Reduced ability to take breast or bottle feeds.
  • Shortness of breath.
  • Older children may complain of chest pain.
  • Swelling in lower legs, belly, or veins of the neck.
  • Bluish skin, which is medically called cyanosis.

The symptoms of the diseases causing heart murmur overlap with other conditions. For this reason, it is essential to take your baby to the doctor right away for an accurate diagnosis.

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How Are Problematic Heart Murmurs In Babies Diagnosed?

The following are the diagnostic methods and tools used to determine the underlying problem causing the heart murmur:

  • The grade of murmur: The intensity of the murmur can tell your doctor
  • if it is a benign or severe condition. A heart murmur can be graded from levels one to six, with grade one being the least severe, soft and only audible under specific conditions while grade six is when the disturbance is audible even without the stethoscope (10). The doctor can then determine if it is an innocent murmur or due to an underlying heart condition.
  • Location of murmur: A doctor will listen to the murmur at four points on the chest, which lie above the crucial parts of the heart. Any malfunctioning here could cause an abnormal heart murmur. The location of the heart murmur helps determine what’s causing it.
  • Chest X-ray: An X-ray helps to detect any chest anomalies that could have induced the heart murmur. The test gives an outline of the heart, which is the first step in further assessing the problem.

[ Read: Asperger’s Syndrome In Toddlers ]

  • Echocardiogram: This procedure is an imaging test, similar to an abdomen ultrasound. In this case, the probe is placed on the chest. There are several variations of echocardiography, and the doctor will suggest one that is best for your baby (11).
  • Electrocardiogram (EKG or ECG): This procedure measures the heartbeat using small electrodes attached to plastic plates or patches that are taped to the child’s torso and the limbs (12). Each electrode is wired to a machine that reads the heart’s electrical activity, which is recorded in the form of an electrocardiograph. The doctors assess the graph to determine the cause of the heart murmur.Treatment for abnormal heart murmurs depends on what’s causing them. Keep reading for details.

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How Is Heart Murmur In Babies Treated?

You may note that heart murmur is not a disease. But it could be a symptom of an underlying disease. Therefore, it needs testing to identify the cause behind the murmur.

Some conditions that cause a heart murmur can go away as the baby grows older. Other conditions may be chronic but not pose a risk to the baby. But if the underlying condition is a serious one, then the doctor would begin the treatment for the condition.

If the heart murmur is a result of a problem that causes severe symptoms mentioned earlier, then surgery might be an option (13). Usually, only some of the congenital heart defects require invasive treatment procedures as well as medications.

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[ Read: How To Treat Torticollis In Babies ]

Heart murmurs are not as scary as they sound, and the symptom seldom lasts forever. You may not be able to detect the condition on your own at home unless you keep your ear to the baby’s chest and know what to hear! Nevertheless, heart murmurs are quite likely to be detected in a routine checkup of the baby. Early detection can ensure your baby has fewer problems with the condition.

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Do you have any experiences to share? Tell us about it in the comments section.

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Rohit Garoo is a writer-turned-editor with over 9 years of experience in content writing, editing, and content marketing. He did his bachelors in Science at St. Xavier's College, Hyderabad, and masters in Business Administration at Osmania University.

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